Put yourself in ebay's shoes.
Their biggest problem in the past, the thing that turned off buyers in droves, was the fear that sellers would just take off into the sunset with the money. I was a victim of that and the seller was someone with years of successful sporadic selling under her belt. Then just after I bought, paying into her bank account because she told me her paypal was playing up, there was an absolute deluge of negs and she was off ebay.
With the advent of paypal though, it's ebay that would cop the loss if a seller came on, sold a heap, then instantly withdrew the money and took off.
That's why there is a 21 day hold, to give them some sort of window of opportunity to stop any short term scammers.
It's not as if they keep the money forever & I think there are ways to get hold of it earlier if you can prove delivery etc.
It's not a foolproof system but it probably helps to limit some damage.
There is one way ebay could overcome an awful lot of problems and conflicts and it would be if they set up a sort of Amazon structure, where they took control of stock & delivery. If that happened, I think casual sellers or occasional sellers would have to go elsewhere so be careful what you wish for.
